title: Abscisic acid alleviates iron deficiency by promoting root iron reutilization and transport from root to shoot in Arabidopsis.
abstract: Abscisic acid (ABA) has been demonstrated to be involved in iron (Fe) homeostasis, but the underlying mechanism is largely unknown. Here, we found that Fe deficiency induced ABA accumulation rapidly (within 6 h) in the roots of Arabidopsis. Exogenous ABA at 0.5 μM decreased the amount of root apoplastic Fe bound to pectin and hemicellulose, and increased the shoot Fe content significantly, thus alleviating Fe deficiency-induced chlorosis. Exogenous ABA promoted the secretion of phenolics to release apoplastic Fe and up-regulated the expression of AtNRAMP3 to enhance reutilization of Fe stored in the vacuoles, leading to a higher level of soluble Fe and lower ferric-chelate reductase (FCR) activity in roots. Treatment with ABA also led to increased Fe concentrations in the xylem sap, partially because of the up-regulation of AtFRD3, AtYSL2 and AtNAS1, genes related to long-distance transport of Fe. Exogenous ABA could not alleviate the chlorosis of abi5 mutant resulting from the significantly low expression of AtYSL2 and low transport of Fe from root to shoot. Taken together, our data support the conclusion that ABA is involved in the reutilization and transport of Fe from root to shoot under Fe deficiency conditions in Arabidopsis.
authors.affiliation: Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, College of Life Science, Zhejiang University, Hangzhou, 310058, China.
authors.forename: Gui Jie
authors.initials: GJ
authors.lastname: Lei
authors.forename: Xiao Fang
authors.initials: XF
authors.lastname: Zhu
authors.forename: Zhi Wei
authors.initials: ZW
authors.lastname: Wang
authors.forename: Fang
authors.initials: F
authors.lastname: Dong
authors.forename: Ning Yu
authors.initials: NY
authors.lastname: Dong
authors.forename: Shao Jian
authors.initials: SJ
authors.lastname: Zheng
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism / Q000494:pharmacology*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D007501:Iron / Q000378:metabolism*; D000090463:Iron Deficiencies; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism*; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism*; D012995:Solubility; D014617:Vacuoles / Q000187:drug effects / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D027682:Cation Transport Proteins; C504141:YSL2 protein, Arabidopsis; D002734:Chlorophyll; D000040:Abscisic Acid; D007501:Iron
keywords: ABA-responsive elements; abi5; apoplast; cell wall; long-distance transport; phenolics.